WHEN many of the seventh-graders at the James P. Timilty Middle School in Roxbury, Mass., first read the following scenario in their class workbook, they understood it well: ``Your friends don't plan on staying in school past age 17, so why should you? You think that once you drop out you will be able to earn money for all the things you want - clothes, cars, and good times. You also think others will respect you more because you'll have a job.''

After a year of Junior Achievement classes, however, including one called ``The Economics of Staying in School,'' many of these students say they have changed their minds about dropping out. ``Before, I thought [school] wasn't worth it,'' says Tiffany Williams. ``Now I know that, with no education, you aren't going to get paid too much.''

Junior Achievement is celebrating its 75th anniversary this year. Over time, the organization has evolved from an after-school program focusing on job skills for high school students to an in-school, kindergarten-12 curriculum designed to educate students to value free enterprise, understand business and economics, and be work-force ready. Junior Achievement relies entirely on volunteers from the business community and gets the majority of its funding from corporate donations.

``In the early '70s, we realized we weren't reaching a broad base of students, that we were not reaching the kids who'd benefit the most,'' says Ed Grocholski, spokesman at Junior Achievement headquarters in Colorado Springs, Colo. The move, in 1974, into middle schools was based on the premise that students should know how to handle personal finances by the time they get to high school.

This past school year, the elementary school segment was fully launched in response to an even more urgent problem: ``Over 80 percent of school dropouts can be identified by the second or third grades,'' says Ron Cody, president of Junior Achievement of the Upper Midwest, based in Minneapolis. The Twin Cities were among 20 pilot programs around the country serving elementary school students.

``We ask why economic education is not required curriculum in every school in the country,'' Mr. Cody says. ``Kids who don't understand how the economic system works have the deck stacked against them.''

More than 40,000 K-12 students in the Minnesota region were enrolled in Junior Achievement classes this year; approximately 1,580 volunteers worked in about 336 schools. ``The best measure of success is demand,'' Cody says. ``The demand was so great that we could not possibly respond to the number of requests from elementary school teachers, for example.''

With demand comes the need for an increase in funding. In general, corporate funding across the country has been flat, Cody says. Junior Achievement has been fortunate in that no programs have been cut, but the organization still needs to develop new sources of funding, he says. Staff members work at cultivating relationships with local businesses to encourage both volunteers and contributions. ``Dollars usually follow volunteers,'' Cody says.

Finding qualified volunteers, however, is one of Junior Achievement's greatest difficulties, he says. ``We've started looking to the community at large because there are not enough people in business to meet the demand.'' Though Junior Achievement still requires that volunteers for the middle and high school segments have a corporate background, the organization is looking for parents, grandparents, and college students to teach elementary school classes.

Starting in September, New Hampshire high school teachers who want their students to participate in Junior Achievement will simply have to turn on the TV. Junior Achievement of Northern New England is participating in a national pilot program to broadcast classes on public television. ``The public TV intitiative covers a large number of students,'' says president Bill Annino. ``One reason we are doing it is because there are not a lot of business people to draw upon.''

A volunteer's experience

When Jacintha Hayes, a senior insurance underwriter at John Hancock Mutual Life Insurance in Boston, decided to become a Junior Achievement volunteer, she was hoping to teach elementary school age children. When she was asked to work with seventh-graders at the Timilty school instead, she says she worried the students ``would be a tough sell.''

``I found just the opposite,'' Ms. Hayes says. ``As long as it was interesting to them, as long as I ... make it as real to them as possible, then I think I'm getting through.''

Her goal, she says, is to help the students understand what it will cost to drop out of school, as well as what an education costs. Timilty classmates Jeffrey Jobson, Steven Davenport, and Tommy Cummings say they have been learning a lot. With heads bent over their workbooks, the boys try to figure out how much it will cost to rent an apartment, pay for utilities, lease a car, and buy food - all on the salary they will make if they drop out of school.

What they discover is they will have to share an apartment, eat less than they would like to, and stint on new clothes. And what about new compact discs and a movie each week? ``No way,'' Tommy says.